In order to facilitate the operation of a vehicle, technical functions are increasingly integrated into the motor vehicle. The user friendliness is increased and malfunctions, such as an unclosed lateral door, can be prevented. A convenience function is that the lateral doors are automatically closed. Closure hereby occurs when the user only lightly closes the lateral door. Consequently, the lateral door latch only reaches a pre-ratchet position from where the lateral door is automatically closed completely. This facilitates operation for the user to the extent that only small forces are required for complete closure of a motor vehicle door. Independent closure can also be advantageous, for example, when large door and/or large sealing pressures are opposed on the doors during closure.
If lateral doors are named here as an example, this shall not apply restrictively, but the actuator unit with the actuating element also relates to other functions in the motor vehicle, such as electromotive closure of a front flap, a tailgate or a sliding door. However, these are in turn also only examples which do not limit the area of application of the actuator unit. Instead, the actuator unit can always be used when forces need to be introduced into a functional unit of a motor vehicle using a Bowden cable. For example, the actuator unit can be part of a closure drive for a motor vehicle latch. By means of the closure unit, a not yet completely dosed lateral door present in the pre-ratchet, for example, can be transferred into a main ratchet.
The pre-ratchet and main ratchet define both safety-related closure positions of a motor vehicle lateral door, in which an incompletely closed door, which is located in a pre-ratchet, for example, needs to be maintained in this open position. The lateral door is then fully closed in the main ratchet. The closure drive must dose the door against the force of the surrounding door seal during electrical dosure, whereby according to the size of the door different forces need to be provided by the closure drive.
From DE 20 2008 007 310 U1 a motor vehicle door seal with a locking mechanism and a closure device with an electrical drive has become known, whereby the closure device acts on the locking mechanism of the motor vehicle door latch. Using a lifting mechanism which acts directly on the locking mechanism via a closure pawl, the locking mechanism can be transferred from a pre-ratchet to a main ratchet. The lever mechanism used for this purpose, including the closure pawl, is activated via a spindle drive. The spindle nut in turn is moved over the spindle via a motor with a downstream gearbox. During closure, the spindle nut executes a forwards movement, whereby the locking mechanism consisting of a catch and a pawl is transferred from a pre-ratchet position into a main ratchet position.
From DE 10 2012 218 650 A 1 an actuator unit with an actuator and a drive unit for movement of the actuator and a Bowden cable connected to the actuator have become known. An actuator unit and in particular a closure drive for a motor vehicle latch is revealed, which in turn is equipped with an electrical drive and a spindle gear. The actuator can be connected to the spindle and conducted in the housing in a linear manner. A Bowden cable is connected to the actuator, so that the Bowden cable core can be operated by means of the spindle and the actuator. A locking mechanism can be transferred from a pre-ratchet into a main ratchet by means of the Bowden cable, for example, whereby a tensile force can preferably be transferred to a motor vehicle latch by the actuator or the closure drive.
A problem present in the further development of motor vehicle latches or actuator units or closure drives is that, on the one hand large forces need to be transmitted and on the other hand a distortion of the actuator should be prevented. Distortion of the actuator should be executed in such a way where possible that, on the one hand, safe conduction of the actuator is guaranteed and, furthermore, transmission of the forces which is as optimum as possible by the actuator needs to be guaranteed. This problem is complicated by the fact that the automotive industry is striving towards making motor vehicles lighter overall.